Brad Pitt’s new zombie blockbuster, World War Z,  is much more about what happened off the screen than on it.

Pitt, who also produces, plays Gerry Lane, a retired United Nations employee who is recruited to help the U.N. again after a global breakout of “rabies.” After a brief jaunt through a chaotic New England, Lane is sent up and down Asia hunting for the pandemic’s patient zero.

World War Z is OK. The film’s biggest crime is not being accurate to or as good as the book on which it’s based, and that’s not fair criticism.

Given the problems with production, it’s a miracle the film is as coherent as it is. Writer Michael Straczynski (uncredited) wrote a script that author Max Brooks was thrilled with and “Ain’t it Cool News” thought could be best picture worthy, but director Marc Forster had Matthew Carnahan rewrite it to focus more on action and drop the first-person retrospective that makes the book so memorable.

Production started before the third act was fully written and was faced with myriad silly, stupid problems. At one point in Israel, shooting was delayed for several hours because they didn’t order enough food for all the extras. They got into trouble with the Hungarian anti-terrorism division because their 85 prop assault rifles may or may not have been functional weapons.

By the end of re-shooting, which encompassed the entire third act, Pitt and Forster weren’t on speaking terms. After loving the first script, Brooks was upset with and distanced himself from the final product.

The zany production brings the movie’s strangest flaw into relief. In the third act, the movie’s subject abruptly changes from a search for patient zero to a half-hazard attempt at developing a vaccine. It very much feels like one movie’s head got placed on another one’s body.

World War Z is at least mildly entertaining. We get to see zombie hordes on an unprecedented scale and a world going to a confused, panicky Hell. Large-scale scenes, like zombies on a plane, haven’t really been done before, and they capture the global feel the movie is going for.

It’s a serviceable zombie/disaster movie, but subtract some extreme arrogance from all levels of the production and it could have been a great one. Un-invested viewers will enjoy it well enough. Audiences who put more thought into their movie watching will have a little more trouble. And fans of the book will inevitably be left wanting, wondering what could have been. The book is nigh-impossible to translate into a script, but apparently the first one was a doozy. If they’d run with it, who knows how the final product would have ended up?

Plan B Productions seems to view World War Z as a long-term action franchise, so it’ll probably get worse as time goes on. The franchise about zombies will, ironically enough, die and twist into an off-screen zombie, requiring more and more life support and yielding less and less milk with each passing installment. We’ve seen it before, but normally we get at least one stellar movie out of it.

Joshua Knopp is a formerly professional film critic, licensed massage therapist, journalism and film student at the University of North Texas and a staff writer for the NT Daily. He stands with Wendy Davis. For questions, rebuttals and further guidance about cinema, you can reach him at reelentropy@gmail.com. At this point, I’d like to remind you that you shouldn’t actually go to movies and form your own opinions. That’s what I’m here for. Be sure to come back tomorrow for a review of Monsters University.